142 



SITING AND COVERAGE OF GROUND RADARS 



SCALE 1:1,000,000 



CONTOUR INTERVAL 1000 FEET 20 ° 



Figure 42. Topographical map for Example 8. 



Table 3. Prediction of permanent echoes.* 



Distance 

 in miles 



Relative intensities from Figure 40. 

 1.18 1.00 0.75 0.50 0.25 0.10 0.03 



1 MSB MSB MSB MSB MSB MSB MSB 



10 MSB MSB MSB MSB MSB MSB M 



20 MSB MSB MSB MSB MSB M M 

 50 M M M M M M 

 100 M M M M M 



200 M M 



*This table will apply only for the conditions of Example 8. 



In Figure 42 is shown a topographical map of the 

 area. Contours are drawn for the first few thousand 

 feet, and prominent peaks are indicated. From topo- 

 graphical sheets of a 20-ft interval and a scale of 

 2 in. to the mile the profiles of Figures 43 and 44 

 are obtained. From the center of the antenna to the 

 "effective" shielding, the line of sight has been drawn 

 and the angle of the line of sight noted. In some cases, 

 as at 20 degrees (Figure 43) a near sharp ridge is not 



